I have a VPS server running in the cloud. Fully automated server image upgrade/downgrade(by RAM/HDD plans).
The problem is that server upgrade/downgrade takes time and involves total unavailability during this period(up to 30 minutes).
Goal: during this downtime server my website(http://mydomain.here) from different server with some message like "Under construction".
How can I do this?
mydomain.here is hosted on godaddy and uses its DNS(If I call it right). It's pointing with A-record to my VPS's IP address now.
Change in these DNS settings will take more than 30minutes, so it's not an option. How can I find mode "dynamic" DNS? What should I learn?